PDF(Pubmed)
Abstract：
The Douglas-fir twig weevil (Cylindrocopturus furnissi Buchanan) (Coleoptera: Curculionidae) has recently emerged as a significant pest of Christmas trees grown in the Pacific Northwest United States. The larvae girdle and disfigure twigs, which adversely affects tree marketability. Trees produced for export are also routinely destroyed for phytosanitary reasons when C. furnissi is discovered at border crossings. Due to historically being a sporadic and benign pest on planted and natural Douglas-fir (Psuedotsuga menziesii), there is a lack of chemical management options. In laboratory experiments, we assessed the knockdown effects (ability to kill or incapacitate) of 4 insecticides commonly used on Christmas trees: one assay tested knockdown after direct contact for 24 h, and the other assay tested knockdown after being allowed to feed on treated twigs with 2 days, 7 days, and 14 days residuals. Concurrently, we monitored temperature and adult C. furnissi emergence at a noble fir bough farm for 2 years to estimate the ideal degree-day window for applying insecticides. Bifenthrin and esfenvalerate knocked down all weevils on contact within just 4 h, whereas chlorpyrifos and acephate failed to achieve 100% knockdown within 24 h. Only acephate failed to knock down more weevils than the control (water) after feeding on treated twigs, regardless of the insecticide residue age. Degree-day modeling revealed a variable emergence window between the 2 years but 50% of adult emergence occurred between approximately 1,000-1,100 degree days (1st January, 50 °F (10 °C), single sine). Future work should assess the resulting management recommendation: apply bifenthrin or esfenvalerate once annually just after 1,000 growing degree days for 2 or more years prior to harvest.
摘要：
道格拉斯冷杉细枝象鼻虫（CylindrocopturusfurnissiBuchanan）（鞘翅目：Curculionidae）最近已成为美国西北太平洋种植的圣诞树的重要害虫。幼虫腰带和残缺的树枝，这对树木的适销性产生了不利影响。当在过境点发现C.furnissi时，出于植物检疫原因，通常还会销毁用于出口的树木。由于历史上是种植和天然道格拉斯冷杉（Psuedotsugamenziesii）上的零星和良性害虫，缺乏化学品管理选择。在实验室实验中,我们评估了4种常用于圣诞树的杀虫剂的击倒效果（杀死或丧失能力的能力）：一种直接接触24小时后进行击倒试验，和另一个试验测试击倒后被允许在处理过的树枝上喂养2天，7天,和14天的残差。同时,我们监测了一个高贵的杉木树枝农场的温度和成年C.furnissi出现2年，以估计施用杀虫剂的理想度日窗口。联苯菊酯和艾司芬戊酸酯在4小时内击倒了所有接触的象鼻虫，而毒死蜱和乙酰甲胺磷未能在24小时内实现100%击倒。在取食处理过的树枝后，只有乙酰甲胺磷未能击倒比对照（水）更多的象鼻虫，无论杀虫剂残留的年龄。度日建模显示，在2年之间存在一个可变的出现窗口，但50％的成人出现发生在大约1,000-1,100度日之间（1月1日，50°F(10°C),单正弦)。未来的工作应评估由此产生的管理建议：在收获前2年或更多年的1,000度生长日后，每年应用联苯菊酯或艾司芬戊酸酯。
